1. Field of the Invention
The present invention relates to a sanitary napkin which is adapted to deform in accordance with the wearer's body shape, comfortable to wear and less noticeable from the outside during wear.
2. Description of the Related Art
Sanitary napkins (feminine hygiene product intended to be applied to the vaginal opening of a menstruating woman) are typically constructed to include a liquid absorbent layer containing pulp, superabsorbent polymer (SAP), etc. and a liquid-permeable topsheet covering a body surface of the liquid absorbent layer.
When put on with the sanitary napkin applied to the vaginal opening, shorts exert an elastic lifting force in the crotch region. The sanitary napkin, which is intended to be in close contact with the vaginal opening, is preferably deformed by the lifting force in accordance with the shape of the woman's crotch region. However, the liquid absorbent layer, which is mainly of pulp and thick, hinders the sanitary napkin from deforming in accordance with the shape of the crotch region and coming into close contact with the vaginal opening.
When the sanitary napkin is worn in the crotch region, the rear end of the sanitary napkin will be positioned slightly posterior to the anus and face the lower part of the buttocks. Particularly when the sanitary napkin is elongated to prevent leakage of menstrual blood toward the buttocks, the rear end of the sanitary napkin will be positioned near the coccyx. When wearing the shorts with the rear end of the sanitary napkin positioned on the lower part of the buttocks, accordingly, if the liquid absorbent layer is thick and cannot easily be deformed by the lifting force of the shorts in accordance with the cleft of the buttocks, the rear end of the sanitary napkin will be noticeable from the outside when wearing tight-fitting pants or the like.
The following patent documents disclose conventional sanitary napkins with a liquid absorbent layer adapted to deform in accordance with the crotch region or the cleft of the buttocks.
Firstly, Japanese Unexamined Patent Application Publication No. H10-328233 discloses an elongated sanitary napkin whose rear part has a liquid absorbent layer with longitudinally extending compressed grooves. When the shorts exert a lifting force on the compressed grooves, the liquid absorbent layer tends to deform at the compressed grooves in accordance with the cleft of the buttocks.
Secondly, Japanese Unexamined Utility-Model Application Publication No. H04-51930 discloses a sanitary napkin in which a liquid absorbent layer is made more deformable by forming a plurality of slit-like incisions in the liquid absorbent layer. As a result, the sanitary napkin tends to deform in accordance with the wearer's body shape and hardly feels rough.
Thirdly, Japanese Unexamined Patent Application Publication No. 2002-35036 discloses a sanitary napkin in which a liquid absorbent layer is made more flexible by forming a number of through-holes in the liquid absorbent layer.
In the sanitary napkin disclosed in Japanese Unexamined Patent Application Publication No. H10-328233, however, since the density of the liquid absorbent layer is increased at the compressed grooves, a wearer tends to feel uncomfortable when the compressed grooves are pressed against the cleft of the buttocks.
In the sanitary napkins disclosed in Japanese Unexamined Utility-Model Application Publication No. H04-51930 and Japanese Unexamined Patent Application Publication No. 2002-35036, on the other hand, since the liquid absorbent layer has weak tensile strength as a whole due to the slit-like incisions or the through-holes distributed over the liquid absorbent layer, the incisions or the through-holes tend to cause a breakage in the liquid absorbent layer when a wearer moves her body with the sanitary napkin worn in the crotch region.
Moreover, since all the liquid absorbent layers disclosed in the foregoing patent documents are made of a pulp deposition and thick, the sanitary napkins tend to be noticeable from the outside when wearing tight-fitting pants or the like, regardless of whether the liquid absorbent layer can deform in accordance with the crotch region or the cleft of the buttocks.